I have an 1984 190E 2.3. I tried to turn the key in the ignition today and it wouldn't turn at all. The steering wheel was not in the lock position either. Finally after wiggling my key for about 5 minutes the key finally turned. What could be causing this?? Is it anything major?

My second question is that when i first start the car and it's cold out, i give it gas and when it's coming out of first gear you hear a scraping noise. Then there is this rapping that seems to be coming from the back part of the engine. What could this be? Water pump maybe? I know it could be several things, but any ideas would help greatly! Thanks a lot - Ryan :p